1. Field of the Invention
The present invention relates generally to fittings for a bicycle, and more specifically, to a fitting for a bicycle for mounting a device for bicycle such as a meter and a sensor on a component of a bicycle such as a handle and fork.
2. Description of the Background Art
In recent years, bicycles are sometimes provided with speed meters so that cyclists can be easily informed of travel speed, travel distance or the like.
FIG. 6 is a side view showing such a speed meter mounted on a bicycle, FIG. 7 is a view showing encircled portion "X" in FIG. 6 being enlarged, and FIG. 8 is an enlarged cross sectional view taken along line VIII--VIII in FIG. 7.
Referring to FIGS. 6 and 7, a speed meter 30 is mounted on the stem 31 of the handle of a bicycle 24. Front spokes 32 of bicycle 24 are provided with a magnet 26, and the portion of fork 34 corresponding to magnet 26 is provided with a sensor portion 28 for generating a signal every time magnet 26 passes in front of it.
The signal generated by sensor portion 28 is input to speed meter 30 through a cord 11, various operations are performed based on the signal in the meter, and information such as speed and travel distance is given to the user.
Now, referring to FIG. 8, how sensor portion 28 is mounted on fork 34 will be described.
A fitting for bicycle 36 for mounting sensor portion 28 on fork 34 includes a band-shaped fitting body 38 which can be engaged with the grooves and ridges of the fluted portion of sensor 28 on the outer periphery of one open end 25, a packing 40 fit along the inner circumference of fitting body 38, and a fitting screw 42 for fixing one end 25 of fitting body 38 engaged with sensor portion 28 and the other end 27.
Packing 40 is fit along the inner circumference of band-shaped fitting body 38, then both ends of fitting body 38 are opened to be fit around fork 34, and packing 40 will be fit along the inner circumference of fitting body 38 and the outer circumference of fork 34. Sensor portion 28 and the grooves and ridges of the fluted portion at one end 25 of fitting body 38 are engaged with each other, and then the one end 25 and the other end 27 of fitting body 38 and sensor portion 28 are fixed by fitting screw 42. Fitting body 38 is tightened to forks 34 through packing 40, and therefore sensor portion 28 will be fixed to fork 34 by means of fitting for bicycle 36.
Meanwhile, unlike such fitting for bicycle 36 using the fitting screw and the packing, there are fittings for bicycles of cord band type.
FIG. 9 is a perspective view showing how a sensor portion is mounted on a fork with a conventional fitting for bicycles of the cord band type, FIG. 10 is an enlarged cross sectional view taken along line X--X in FIG. 9, and FIG. 11 is an enlarged cross sectional view taken along line XI--XI in FIG. 9.
Referring to FIGS. 9 to 11, a fitting for a bicycle of the cord band type 44 for mounting a sensor portion 29 on a fork 34 includes an integral structure of cord band portions 46a, 46b having a shape like a cord band for bundling the cord of an electrical appliance, and a sensor portion 29. Cord band portion 46b has grooves and ridges of corrugation lengthwise on its outer circumference, and an engaging portion 48 having a protrusion 45 which can be engaged with one of the grooves of the corrugation is provided at an end of cord band portion 46a.
When mounted, engaging portion 48 is manually pressed and the end of cord band portion 46b on the side having the grooves and ridges of corrugation is pulled through engaging portion 48. Thus, the protrusion 45 of engaging portion 48 is gradually engaged with a groove of corrugation of cord band portion 46b near sensor portion 29, then the inner circumference of cord band portion 46b is pressure-contacted to fork 34 and sensor portion 29 is fixed to fork 34.
There are more than one kinds of shapes for the fork of a bicycle, and the forks of so-called mountain bikes are for example often larger than the forks of sports bikes.
The former fitting for a bicycle with a fitting screw and a packing can be adapted to forks of different sizes by changing the thickness of the packing to a limited extent, and fittings of different sizes such as large, medium and small must be usually prepared for one component for a bicycle.
Meanwhile, the latter fitting for a bicycle of cord band type can cope with forks of different sizes by adjusting the degree of tightening the cord band portion. However, since it is tightened in a stepped manner by each groove of corrugation, fine adjustment such as done with the screw type cannot be made. If the protrusion in engagement with one of the grooves of the corrugation is forced to engage with another groove closer to the sensor portion, the cord band portion can be cut away from the sensor portion. Furthermore, since the engaging force between the protrusion and the groove of the corrugation of cord band portion engaging therewith at the engagement portion is constant, tightening too much degrades the reliability of the engaged portion.